The proposed research seeks to provide a more thorough understanding of the PZ-peptidases from mammalian spermatozoa and testes with respect to the subcellular localization, biochemical properties and possible physiological function of these enzymes. The subcellular location of the PZ-peptidase in spermatozoal components will be determined by immunocytochemical techniques, using antibodies raised against a highly purified PZ-peptidase isolated from testes. The PZ-peptidases from bovine testicular tissue and spermatozoal components will be purified to homogeneity by employing a combination of classical and bio-specific fractionation procedures. The biochemical properties of the PZ-peptidase, including susceptibility to inhibitors, requirement for activators and stabilizers, and substrate specificity towards native proteins, peptides and synthetic substrates, will be examined using the purified enzyme preparations. The proline carboxypeptidase from spermatozoa and testes will also be purified and biochemically characterized to assess its possible role in reproductive functions. It is anticipated that the information obtained as a result of these studies may find application in the fields of reproductive biology and fertility regulation.